CN102882818A - Amending method and amending system directing at unbalanced zero intermediate frequency feedback - Google Patents

Abstract

The invention provides an amending method and an amending system directing at an unbalanced zero intermediate frequency feedback, and the amending method and the amending system are used for solving the problems of unobvious effect of the existing amending method and inexact I/Q signal. The method comprises the following steps: sampling a zero intermediate frequency feedback signal, wherein the zero intermediate frequency feedback signal comprises an I signal and a Q signal; respectively counting direct current leakage volumes of the I signal and the Q signal, and performing the direct current amending treatment on the I signal and the Q signal according to the direct current leakage volumes; counting an amplitude ratio of the I signal and the Q signal after the direct current amendment, and performing amplitude amending treatment on the I signal and the Q signal after performing the direct current amendment according to the amplitude ratio; counting a phase position difference between the I signal and the Q signal after amending the phase position, and performing phase position amending treatment on the I signal and the Q signal after performing the amplitude amendment according to the phase position difference; and performing digital distortion factor updating treatment on the I signal and the Q signal after performing the I signal and the Q signal to obtain the I signal and the Q signal to be sent. With the adoption of the amending method and the amending system, the obtained I signal and the Q signal to be sent are more exact.

Description

A kind ofly feed back unbalanced modification method and system for zero intermediate frequency

Technical field

The application relates to communication technical field, particularly relates to a kind ofly feeding back unbalanced modification method and system for zero intermediate frequency.

Background technology

Digital pre-distortion (DigitalPre-Distortion, DPD) (the Analog-to-Digital Converter of the analog to digital converter in the feedback path, ADC) be used for the radiofrequency signal that receives is gathered, the performance of ADC sampling is determined by sampling rate, according to Nyquist's theorem as can be known, sampling rate should be higher than 2 times of signal bandwidth of sampling at least, and the signal of collection just aliasing can not occur, the radiofrequency signal before the reaction sampling that can be complete.And system is carrying out digital pre-distortion when processing, the P that spread bandwidth should be signal bandwidth doubly, therefore, when ADC sampled for spread bandwidth, the sampling rate of ADC should be more than or equal to 2 times spread bandwidth.When actual DPD feedback sample, usually adopt P＞=3, take P=4 as example, adopt 4 rank crosstalk collections, if signal bandwidth is 30MHZ, sampling frequency P＞=rate should be 240MHZ like this.

But in present technology, because the sampling rate of ADC is too low, the low pass filter bandwidth that perhaps ADC arranges in the feedback path is inadequate, therefore can't collect the P rank crosstalk of feedback signal, cause filtered pre-distorted signals frequency spectrum to produce bulge, distortion will appear in the P rank intermodulation P times of signal bandwidth part, and bulge appears in the frequency spectrum left and right sides, thereby causes the signal of collection inaccurate.

For the problems referred to above, present solution is to adopt zero intermediate frequency cross feedback scheme in the DPD feedback path.As shown in Figure 1, the operation principle of zero intermediate frequency feedback is the power amplifier (PowerAmplifier that is coupled to, PA) zero intermediate frequency signals of two quadratures of generation after the frequency conversion of the radiofrequency signal of output process quadrature demodulator, be respectively homophase (In-phase, I) signal and quadrature (Quadrature-phase mutually, Q) signal, these two signals are low pass filtering and limited range enlargement in the I/Q passage subsequently, then i/q signal is become digital signal by the ADC sampling respectively, sends to the DPD processing module after the down-conversion and processes.

But, the orthogonality of the phase place of the i/q signal that very difficult assurance produces in the said method, the unbalance in phase that causes signal, the consistency of produced simultaneously I/Q passage also can change along with the conversion of temperature and time, thereby causes the amplitude imbalance of i/q signal.Therefore in addition, when in the signal process of transmitting and in ADC, processing, all can produce direct current leakage, utilize the method also can be so that the i/q signal that produces is inaccurate.

Problem for above-mentioned zero intermediate frequency quadrature receiving scheme existence, generally all be that transmitting chain or based on feedback link are revised at present, for the correction in the transmitting chain generally by repeatedly sending the method for single-tone, for the method for the correction in the receiver by real time calibration.But in the prior art for the effect of the real-time calibration method of receiver and not obvious.

Summary of the invention

The application's technical problem to be solved provides a kind ofly feeds back unbalanced modification method and system for zero intermediate frequency, to solve existing modification method DeGrain, the inaccurate problem of the i/q signal that obtains.

In order to address the above problem, the application discloses and has a kind ofly fed back unbalanced modification method for zero intermediate frequency, comprising:

The zero intermediate frequency feedback signal is sampled, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature;

Add up respectively the direct current leakage amount of described I signal and Q signal, and respectively described I signal and Q signal are carried out the direct current correcting process according to described direct current leakage amount;

The Amplitude Ratio of the statistics revised I signal of direct current and Q signal, and the described Amplitude Ratio of foundation carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively;

I signal behind the statistics amplitude correction and the phase difference of Q signal, and the described phase difference of foundation carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively;

The revised I signal of phase place and Q signal are carried out the processing of digital pre-distortion coefficient update, obtain I signal to be sent and Q signal.

Preferably, described step of adding up respectively the direct current leakage amount of described I signal and Q signal comprises:

Calculate the mean value dc_ri of all I signals of sampling in the Preset Time section, described mean value dc_ri is defined as the direct current leakage amount of I signal;

Calculate the mean value dc_rq of all Q signals of sampling in the described Preset Time section, described mean value dc_rq is defined as the direct current leakage amount of Q signal.

Preferably, the described direct current leakage amount of described foundation comprises the step that described I signal and Q signal carry out the direct current correcting process respectively:

Respectively each I signal of sampling in the described Preset Time section is deducted the direct current leakage amount of described I signal, obtain the revised I signal of each direct current;

Respectively each Q signal of sampling in the described Preset Time section is deducted the direct current leakage amount of described Q signal, obtain the revised Q signal of each direct current.

Preferably, the step of the Amplitude Ratio of the revised I signal of described statistics direct current and Q signal comprises:

Calculate the summation amp_ri of the revised I signal of all direct currents;

Calculate the summation amp_rq of the revised Q signal of all direct currents;

Calculate the ratio of described summation amp_ri and described summation amp_rq, the perhaps ratio of described summation amp_rq and described summation amp_ri is defined as described ratio the Amplitude Ratio of the revised I signal of described direct current and Q signal.

Preferably, when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq,

The described Amplitude Ratio of described foundation carries out the step that amplitude correction processes to the revised I signal of described direct current and Q signal respectively and comprises:

Respectively the revised I signal of each direct current is defined as the I signal behind each amplitude correction;

Respectively the revised Q signal of each direct current and described Amplitude Ratio are multiplied each other, obtain the Q signal behind each amplitude correction.

Preferably, when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri,

The described Amplitude Ratio of described foundation carries out the step that amplitude correction processes to the revised I signal of described direct current and Q signal respectively and comprises:

Respectively the revised I signal of each direct current and described Amplitude Ratio are multiplied each other, obtain the I signal behind each amplitude correction;

Respectively the revised Q signal of each direct current is defined as the Q signal behind each amplitude correction.

Preferably, the I signal composition of vector RI behind all amplitude corrections, the Q signal composition of vector QI behind all amplitude corrections,

The step of the I signal behind the described statistics amplitude correction and the phase difference of Q signal comprises:

Calculate the angle of described vectorial RI and described vectorial QI;

Calculate the arcsine value of described angle, described arcsine value is defined as I signal behind the described amplitude correction and the phase difference of Q signal.

Preferably, the described phase difference of described foundation comprises the step that the I signal behind the described amplitude correction and Q signal carry out the phase place correcting process respectively:

Respectively the I signal behind each amplitude correction is defined as the revised I signal of each phase place;

Sine value with the I signal behind each amplitude correction and described phase difference multiplies each other respectively, obtains the first numerical value, and the Q signal behind described the first numerical value and the described amplitude correction is corresponding one by one;

Respectively the Q signal behind each amplitude correction is deducted first numerical value corresponding with it, obtain second value;

With the cosine value of each second value divided by described phase difference, obtain the revised Q signal of each phase place respectively.

Preferably, described digital pre-distortion coefficient update is processed and is comprised synchronous calibration, pre-distortion coefficients estimation and pre-distortion.

On the other hand, disclosed herein as well is and a kind ofly feed back unbalanced update the system for zero intermediate frequency, comprising:

Sampling module is used for the zero intermediate frequency feedback signal is sampled, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature;

The direct current correcting module, for the direct current leakage amount of adding up respectively described I signal and Q signal, and the described direct current leakage amount of foundation is carried out the direct current correcting process to described I signal and Q signal respectively;

The amplitude correction module, for the Amplitude Ratio of the statistics revised I signal of direct current and Q signal, and the described Amplitude Ratio of foundation carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively;

The phase place correcting module, for the I signal behind the statistics amplitude correction and the phase difference of Q signal, and the described phase difference of foundation carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively;

Update module is used for the revised I signal of phase place and Q signal are carried out the processing of digital pre-distortion coefficient update, obtains I signal to be sent and Q signal.

Preferably, described direct current correcting module comprises:

I signal direct current leakage amount computing unit for the mean value dc_ri that calculates all I signals of sampling in the Preset Time section, is defined as described mean value dc_ri the direct current leakage amount of I signal;

Q signal direct current leakage amount computing unit for the mean value dc_rq that calculates all Q signals of sampling in the described Preset Time section, is defined as described mean value dc_rq the direct current leakage amount of Q signal.

Preferably, described direct current correcting module also comprises:

I signal direct current amending unit, the direct current leakage amount for respectively each I signal of sampling in the described Preset Time section being deducted described I signal obtains the revised I signal of each direct current;

Q signal direct current amending unit, the direct current leakage amount for respectively each Q signal of sampling in the described Preset Time section being deducted described Q signal obtains the revised Q signal of each direct current.

Preferably, described amplitude correction module comprises:

I signal summation computing unit is for the summation amp_ri that calculates the revised I signal of all direct currents;

Q signal summation computing unit is for the summation amp_rq that calculates the revised Q signal of all direct currents;

The Amplitude Ratio computing unit is used for calculating the ratio of described summation amp_ri and described summation amp_rq, and the perhaps ratio of described summation amp_rq and described summation amp_ri is defined as described ratio the Amplitude Ratio of the revised I signal of described direct current and Q signal.

Preferably, described amplitude correction module also comprises:

The first I signal amplitude correction unit is used for when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, respectively the revised I signal of each direct current is defined as the I signal behind each amplitude correction;

The first Q signal amplitude correction unit is used for respectively the revised Q signal of each direct current and described Amplitude Ratio being multiplied each other when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, obtains the Q signal behind each amplitude correction.

Preferably, described amplitude correction module also comprises:

The second I signal amplitude correction unit is used for respectively the revised I signal of each direct current and described Amplitude Ratio being multiplied each other when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, obtains the I signal behind each amplitude correction;

The second Q signal amplitude correction unit is used for when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, respectively the revised Q signal of each direct current is defined as the Q signal behind each amplitude correction.

Preferably, the I signal composition of vector RI behind all amplitude corrections, the Q signal composition of vector QI behind all amplitude corrections,

Described phase place correcting module comprises:

The angle computing unit is for the angle that calculates described vectorial RI and described vectorial QI;

The phase difference calculating unit is used for calculating the arcsine value of described angle, and described arcsine value is defined as I signal behind the described amplitude correction and the phase difference of Q signal.

Preferably, described phase place correcting module also comprises:

I signal phase place amending unit is used for respectively the I signal behind each amplitude correction being defined as the revised I signal of each phase place;

The unit that multiplies each other is used for respectively the sine value of the I signal behind each amplitude correction and described phase difference is multiplied each other, and obtains the first numerical value, and the Q signal behind described the first numerical value and the described amplitude correction is corresponding one by one;

Addition unit is used for the Q signal behind each amplitude correction being deducted first numerical value corresponding with it respectively, obtains second value;

Q signal phase place amending unit is used for respectively with the cosine value of each second value divided by described phase difference, obtains the revised Q signal of each phase place.

Preferably, described update module comprises:

The synchronous calibration unit is used for the revised I signal of phase place and Q signal are carried out synchronous calibration;

The pre-distortion coefficients evaluation unit is used for the I signal behind the synchronous calibration and Q signal are carried out the pre-distortion coefficients estimation;

The pre-distortion unit is used for utilizing described pre-distortion coefficients that I signal and Q signal are carried out pre-distortion.

Compared with prior art, the application comprises following advantage:

The application proposes a kind of unbalanced modification method when adopting the zero intermediate frequency feedback for the DPD feedback path, at first the zero intermediate frequency signals that receives DPD feedback path feedback is sampled, then for direct current leakage, amplitude imbalance and three kinds of situations of unbalance in phase the signal of sampling is added up and revised respectively.Concrete, carry out first statistics and the correction of direct current leakage, then take the correction result of direct current as the basis, carry out statistics and the correction of amplitude imbalance, take the correction result of amplitude as the basis, carry out statistics and the correction of unbalance in phase again.Therefore, the application samples by the zero intermediate frequency feedback signal of once feeding back for the DPD feedback path, can carry out statistics and the makeover process of above-mentioned three kinds of situations, and need not repeatedly iteration, has improved treatment effeciency.And the application carries out the digital pre-distortion coefficient update to the signal after revising again and processes, thereby make the I signal to be sent and the Q signal that obtain more accurate by the zero intermediate frequency feedback signal is revised.

Description of drawings

Fig. 1 is the circuit diagram when the DPD feedback path adopts the zero intermediate frequency cross feedback in the prior art;

Fig. 2 is the described overall structure figure that adopts the zero intermediate frequency cross feedback and revise feeding back imbalance at the DPD feedback path of the embodiment of the present application;

Fig. 3 is the embodiment of the present application one described a kind of flow chart that feeds back unbalanced modification method for zero intermediate frequency;

Fig. 4 is the embodiment of the present application two described a kind of flow charts that feed back unbalanced modification method for zero intermediate frequency;

Fig. 5 is the schematic diagram of the described statistics direct current leakage of the embodiment of the present application amount, Amplitude Ratio and phase difference;

Fig. 6 is the schematic diagram of the described direct current correction of the embodiment of the present application, amplitude correction and phase place correction;

Fig. 7 is the schematic diagram of the overall process of the described statistics of the embodiment of the present application and correction;

Fig. 8 is that the embodiment of the present application is described for the uneven data access schematic diagram that carries out in the makeover process of zero intermediate frequency feedback;

Fig. 9 is the embodiment of the present application three described a kind of structured flowcharts that feed back unbalanced update the system for zero intermediate frequency.

Embodiment

For above-mentioned purpose, the feature and advantage that make the application can become apparent more, below in conjunction with the drawings and specific embodiments the application is described in further detail.

The application at first samples to the zero intermediate frequency signals that receives DPD feedback path feedback, then for direct current leakage, amplitude imbalance and three kinds of situations of unbalance in phase the signal of sampling is added up and revised respectively, again the signal after revising is carried out the digital pre-distortion coefficient update at last and process, thereby make the I signal to be sent and the Q signal that obtain more accurate.

As shown in Figure 2, be the overall structure figure that adopts the zero intermediate frequency cross feedback and revise feeding back imbalance at the DPD feedback path.

At first, simply introduce the overall process of signal feedback:

As can be seen from Figure 2, in transmission channel, high speed predistortion output signal i/q signal is respectively by digital analog converter (Digital to analog converter, DAC) output to I/Q two-way analog channel, i/q signal carries out respectively after DAC conversion and the low pass filter filtering, input to quadrature modulator, then by quadrature modulator radiofrequency signal is exported to PA, PA sends radiofrequency signal again by radio-frequency antenna.

Simultaneously, the DPD feedback path can be coupled to the radiofrequency signal of PA output, then send it to quadrature demodulator (described quadrature demodulator is comprised of pair of orthogonal frequency mixer (Quadrature Mixer)), after the quadrature demodulator frequency conversion, produce zero intermediate frequency signals I signal and the Q signal of two quadratures, these two signals are exaggerated device limited range enlargement and low pass filter filtering subsequently, then i/q signal is become digital signal by the ADC sampling respectively, gives Base-Band Processing after the down-conversion.

Wherein, the radiofrequency signal of the PA output that receives of quadrature demodulator is that rf_rx (t) is:

rf_rx(t)＝I(t)cOS(2πf _RFt)-Q(t)sin(2πf _RFt)

Wherein, the I signal of I (t) for receiving, the Q signal of Q (t) for receiving, f _RFBe rf frequency.

After the processing through the DPD feedback path, the signal that sends to the DPD processing module is respectively:

$g_i=1+\frac{\mathrm{\α}}{2},$ $g_q=1-\frac{\mathrm{\α}}{2}$

Wherein, g is gain,

Be phase error, t represents the time, h _Lpf(t) be simulation low-pass filter, be used for the filtering high-frequency signal, ri (t) is for sending to the I signal of DPD processing module, and rq (t) is for sending to the Q signal of DPD processing module.

Because the application adopts zero intermediate frequency feedback, so local frequency equals rf frequency, i.e. f _LO=f _RF, the I signal and the Q signal that then draw at last are respectively:

Formula 1:

$\mathrm{ri}\left(t\right)=\left\{\right[I\left(t\right)\cos \left(2\mathrm{\π}{f}_{\mathrm{RF}}t\right)-Q\left(t\right)\sin \left(2\mathrm{\π}{f}_{\mathrm{RF}}t\right)]\·2\cos (-2\mathrm{\π}{f}_{\mathrm{RF}}t)\·g_q+{\mathrm{\Δd}}_i\left(t\right)\}\⊗h_{\mathrm{lpf}}\left(t\right)$

$=\left\{\right[I\left(t\right)+I\left(t\right)\cos \left(2{\mathrm{\ω}}_{\mathrm{RF}}t\right)-Q\left(t\right)\cos \left({2\mathrm{\ω}}_{\mathrm{RF}}t\right)]\·g_i+{\mathrm{\Δd}}_i\left(t\right)\}\⊗h_{\mathrm{lpf}}\left(t\right)$

$=I\left(t\right)\·g_i+{\mathrm{\Δd}}_i\left(t\right)$

Formula 2:

$\mathrm{rq}\left(t\right)=\left\{\right[I\left(t\right)\cos \left(2\mathrm{\π}{f}_{\mathrm{RF}}t\right)-Q\left(t\right)\sin \left(2\mathrm{\π}{f}_{\mathrm{RF}}t\right)]\·2\sin (-2\mathrm{\π}{f}_{\mathrm{RF}}t)\·g_q+{\mathrm{\Δd}}_q\left(t\right)\}\⊗h_{\mathrm{lpf}}\left(t\right)$

$=\left\{\right[I\left(t\right)\sin \left(\mathrm{\θ}\right)+I\left(t\right)\sin ({2\mathrm{\ω}}_{\mathrm{RF}}t-\mathrm{\θ})-Q\left(t\right)\cos ({2\mathrm{\ω}}_{\mathrm{RF}}t-\mathrm{\θ})+Q\left(t\right)\cos \left(\mathrm{\θ}\right)]\·g_q+{\mathrm{\Δd}}_q\left(t\right)\}\⊗h_{\mathrm{lpf}}\left(t\right)$

$=[I\left(t\right)\sin \left(\mathrm{\θ}\right)+Q\left(t\right)\cos \left(\mathrm{\θ}\right)]\·g_q+{\mathrm{\Δd}}_q\left(t\right)$

Wherein, ω _RF=2 π f _RF, high-frequency signal 2 ω _RFBe low pass filtering device h _Lpf(t) filtering.

In the embodiment of the present application, utilize the DPD processing module that above-mentioned I signal and Q signal are revised, require the phase error theta of I signal and Q signal=0, gain g _i=g _q, direct current leakage Δ d _i(t)=Δ d _q(t)=0.For concrete modification method, will discuss in detail in the following embodiments.

With reference to Fig. 3, show that the embodiment of the present application one is described a kind ofly feeds back the flow chart of unbalanced modification method for zero intermediate frequency, described method comprises:

Step S301 samples to the zero intermediate frequency feedback signal, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature.

In conjunction with Fig. 2, this step is the process of catching feedback signal of carrying out in the DPD processing module among Fig. 2.Respectively I signal Ri and the Q signal Rq of two ADC outputs in the DPD feedback path are sampled, in sampling process, the I signal of sampling and Q signal are a plurality of.

Add up respectively and revise according to I signal and Q signal that these samplings obtain, be i.e. " feedback signal direct current leakage and unbalanced statistics " described in Fig. 2, and " direct current of feedback signal and mirror image correction " two processes.Wherein, the feedback signal imbalance comprises amplitude imbalance and two kinds of situations of unbalance in phase, and the mirror image correction comprises amplitude correction and two kinds of situations of phase place correction.Again revised signal is carried out the digital pre-distortion coefficient update at last and process, can obtain more accurately signal to be sent.

Need to prove, in the embodiment of the present application, be divided into three phases for the I signal of sampling and the statistic processes of Q signal, at first carry out direct current statistics and correction, carry out again amplitude statistics and correction, carry out at last phase place statistics and correction.Be that the embodiment of the present application is after adding up for a kind of situation, namely carry out the makeover process for this kind situation, after complete for the correction of this kind situation, with the primary signal of revised result as next step statistics, carry out again next step statistics and makeover process.

Step S302, the direct current leakage amount of adding up respectively described I signal and Q signal, and the described direct current leakage amount of foundation is carried out the direct current correcting process to described I signal and Q signal respectively.

Step S303, the Amplitude Ratio of the statistics revised I signal of direct current and Q signal, and the described Amplitude Ratio of foundation carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively.

Step S304, the I signal behind the statistics amplitude correction and the phase difference of Q signal, and the described phase difference of foundation carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively.

Above-mentioned steps S302-step S304 describes is the process of carrying out direct current correction, amplitude correction and phase place correction for I signal and Q signal respectively.Step S303 adds up and revises as primary signal with the revised I signal of the resulting direct current of step S302 and Q signal, and I signal and the Q signal of step S304 after with the resulting amplitude correction of step S303 added up and revised as primary signal.For the concrete processing procedure of step S302-step S304, will discuss in detail in the following embodiments.

Step S305 carries out the processing of digital pre-distortion coefficient update to the revised I signal of phase place and Q signal, obtains I signal to be sent and Q signal.

After I signal and Q signal are carried out the phase place correction, also to carry out the digital pre-distortion coefficient update to the revised I signal of phase place and Q signal and process, thereby obtain I signal to be sent and Q signal.

The application proposes a kind of unbalanced modification method when adopting the zero intermediate frequency feedback for the DPD feedback path, at first the zero intermediate frequency signals that receives DPD feedback path feedback is sampled, then for direct current leakage, amplitude imbalance and three kinds of situations of unbalance in phase the signal of sampling is added up and revised respectively.Concrete, carry out first statistics and the correction of direct current leakage, then take the correction result of direct current as the basis, carry out statistics and the correction of amplitude imbalance, take the correction result of amplitude as the basis, carry out statistics and the correction of unbalance in phase again.Therefore, the application samples by the zero intermediate frequency feedback signal of once feeding back for the DPD feedback path, can carry out statistics and the makeover process of above-mentioned three kinds of situations, and need not repeatedly iteration, has improved treatment effeciency.And the application carries out the digital pre-distortion coefficient update to the signal after revising again and processes, thereby make the I signal to be sent and the Q signal that obtain more accurate by the zero intermediate frequency feedback signal is revised.

With reference to Fig. 4, show that the embodiment of the present application two is described a kind ofly feeds back the flow chart of unbalanced modification method for zero intermediate frequency, the detailed process that this embodiment has described direct current statistics and correction, amplitude statistics and correction and phase place statistics and revised.Described method comprises:

Step 401 is sampled to the zero intermediate frequency feedback signal, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature.

Step S402, the direct current leakage amount of adding up respectively described I signal and Q signal.

For the I signal that samples and Q signal, at first need to add up respectively the direct current leakage amount of I signal and Q signal.

Because what the 3G/4G system sent all is modulation signal, modulation signal 4 mutually the distributions of limit be at random, after therefore a large amount of I signal of sampling or Q signal being superposeed, its average is near zero, the signal of statistics is more, average just more approaching zero.Therefore, by I signal and the Q signal of statistics in a period of time, calculate respectively more during this period of time in the average of I signal and Q signal, just the average of the signal that calculates can be thought respectively the direct current leakage amount of I signal and Q signal.

Concrete, this step S402 comprises:

Step a1 calculates the mean value dc_ri of all I signals of sampling in the Preset Time section, described mean value dc_ri is defined as the direct current leakage amount of I signal.

Wherein, for described Preset Time section, those skilled in the art get final product according to actual conditions setting, and the application is not limited concrete numerical value.

The direct current leakage measurer body of described I signal calculates by following formula:

$\mathrm{dc}\_\mathrm{ri}=\frac{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{ri}}_0\left(k\right)}{K}$

Wherein, ri ₀(k) be the I signal of initial sampling.

Step a2 calculates the mean value dc_rq of all Q signals of sampling in the described Preset Time section, described mean value dc_rq is defined as the direct current leakage amount of Q signal.

Concrete by following formula calculating:

$\mathrm{dc}\_\mathrm{rq}=\frac{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\mathrm{rq}}_0\left(k\right)}{K}$

Wherein, rq ₀(k) be the Q signal of initial sampling.

Step S403 carries out the direct current correcting process to described I signal and Q signal respectively according to described direct current leakage amount.

After counting respectively the direct current leakage amount of I signal and Q signal, each I signal with sampling just can obtain the revised signal of each direct current with the direct current leakage amount that each Q signal deducts correspondence respectively, thereby reaches the purpose that eliminates direct current leakage.

Concrete, this step S403 comprises:

Steps A 1 deducts each I signal of sampling in the described Preset Time section respectively the direct current leakage amount of described I signal, obtains the revised I signal of each direct current.

Concrete by following formula calculating:

ri ₁(k)＝ri ₀(k)-dc_ri，k＝1…K

Wherein, ri ₁(k) be the revised I signal of direct current.

Steps A 2 deducts each Q signal of sampling in the described Preset Time section respectively the direct current leakage amount of described Q signal, obtains the revised Q signal of each direct current.

Concrete by following formula calculating:

rq ₁(k)＝rq ₀(k)-dc_rq，k＝1…K

Wherein, rq ₁(k) be the revised Q signal of direct current.

Step S404, the Amplitude Ratio of the statistics revised I signal of direct current and Q signal.

Through after the above-mentioned direct current correction, take the revised I signal of above-mentioned direct current and Q signal as primary signal, add up the Amplitude Ratio of the revised I signal of described direct current and Q signal.

Because what the 3G/4G system sent all is modulation signal, Quadrature Phase Shift Keying modulation signal (Quadrature Phase Shift Keying for example, QPSK), quadrature amplitude modulation signal (Quadrature Amplitude Modulation, 64QAM) etc., wherein, the amplitude of I signal and Q signal all is the same, and only sign is different.Therefore, after the multicarrier stack, the I signal of statistics and the amplitude of Q signal should be the same in theory in a period of time, if the amplitude of statistics is different in a period of time, the amplitude that i/q signal then is described is because the gain difference of I/Q passage causes.

This step S404 specifically comprises:

Step b1 calculates the summation amp_ri of the revised I signal of all direct currents.

Concrete by following formula calculating:

$\mathrm{amp}\_\mathrm{ri}=\underset{k=1}{\overset{K}{\mathrm{\Σ}}}\left|{\mathrm{ri}}_1\left(k\right)\right|$

Step b2 calculates the summation amp_rq of the revised Q signal of all direct currents.

Concrete by following formula calculating:

$\mathrm{amp}\_\mathrm{rq}=\underset{k=1}{\overset{K}{\mathrm{\Σ}}}\left|{\mathrm{rq}}_1\left(k\right)\right|$

Step b3 calculates the ratio of described summation amp_ri and described summation amp_rq, and the perhaps ratio of described summation amp_rq and described summation amp_ri is defined as described ratio the Amplitude Ratio of the revised I signal of described direct current and Q signal.

Described Amplitude Ratio comprises following two kinds of situations in the embodiment of the present application:

(1) described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, namely

$\mathrm{gq}=\frac{\mathrm{amp}\_\mathrm{ri}}{\mathrm{amp}\_\mathrm{rq}}$

(2) described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, namely

$\mathrm{gi}=\frac{\mathrm{amp}\_\mathrm{rq}}{\mathrm{amp}\_\mathrm{ri}}$

Step S405 carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively according to described Amplitude Ratio.

After the Amplitude Ratio that counts the revised I signal of direct current and Q signal, still take the revised I signal of above-mentioned direct current and Q signal as primary signal, respectively the revised I signal of described direct current and Q signal are carried out the amplitude correction processing, thereby reach the purpose that eliminates amplitude imbalance.

Concrete, for two kinds of situations of above-mentioned Amplitude Ratio, this step S405 carries out different makeover process:

(1) when described Amplitude Ratio is the ratio gq of described summation amp_ri and described summation amp_rq, this step S405 specifically comprises:

Step B1 is defined as the revised I signal of each direct current respectively the I signal behind each amplitude correction.

Concrete by following formula calculating:

ri ₂(k)＝ri ₁(k)，k＝1…K

Step B2 multiplies each other the revised Q signal of each direct current and described Amplitude Ratio respectively, obtains the Q signal behind each amplitude correction.

Concrete by following formula calculating:

rq ₂(k)＝rq ₁(k)·gq，k＝1…K

(2) when described Amplitude Ratio is the ratio gi of described summation amp_rq and described summation amp_ri, this step S405 specifically comprises:

Step B1 ' multiplies each other the revised I signal of each direct current and described Amplitude Ratio respectively, obtains the I signal behind each amplitude correction.

Concrete by following formula calculating:

ri ₂(k)＝ri ₁(k)·gi，k＝1…K

Step B2 ' is defined as the revised Q signal of each direct current respectively the Q signal behind each amplitude correction.

Concrete by following formula calculating:

rq ₂(k)＝rq ₁(k)，k＝1…K

Wherein, ri ₂(k) be I signal behind the amplitude correction, rq ₂(k) be Q signal behind the amplitude correction.

Step S406, the I signal behind the statistics amplitude correction and the phase difference of Q signal.

Through after the above-mentioned amplitude correction, be take the I signal behind the above-mentioned amplitude correction and Q signal as primary signal, add up I signal behind the described amplitude correction and the phase difference of Q signal.

According to formula 2 as can be known, after carrying out direct current correction and amplitude correction, I signal ri (t) and Q signal rq (t) are respectively:

ri(t)＝I(t)

rq(t)＝[I(t)sin(θ)+Q(t)cos(θ)]

In the embodiment of the present application, the target that reach is the phase difference θ=0 of I signal and Q signal, and the Q signal rq (t) that then receives just in time is the primary signal Q (t) that transmitter channels sends, that is:

rq(t)＝[I(t)sin(0)+Q(t)cos(0)]＝Q(t)

And if θ ≠ 0, then Q signal rq (t) is:

Rq (t)=Q (t) cos (θ)+ri (t) sin (θ) formula 3

If need to obtain original Q signal Q (t), then derive and can draw by formula 3:

Q(t)cos(θ)＝rq(t)-ri(t)sin(θ)

Thereby derive original Q (t) signal be:

$Q\left(t\right)=\frac{\mathrm{rq}\left(t\right)-\mathrm{ri}\left(t\right)\sin \left(\mathrm{\θ}\right)}{\cos \left(\mathrm{\θ}\right)}$

If I/Q two paths of signals quadrature then exists Therefore, the application statistics behind the amplitude correction I signal and during the phase difference of Q signal, calculate according to the angle of I signal and Q signal composition of vector.

I/Q two paths of signals ri (k) and the rq (k) of feedback signal are a series of data, so in the present embodiment, I signal composition of vector RI behind all amplitude corrections, Q signal composition of vector QI behind all amplitude corrections, think that RI and QI are the K dimensional vectors, with the angle of Pest as these two K dimensional vectors.

The angle of K dimensional vector RI and QI calculates according to following formula:

$P_{\mathrm{est}}=\arcsin \frac{[\mathrm{RI},\mathrm{RQ}]}{\left|\right|\mathrm{RI}\left|\right|\left|\right|\mathrm{RQ}\left|\right|}$

Therefore, this step S406 specifically comprises:

Step c1 calculates the angle of described vectorial RI and described vectorial QI.

Concrete by following formula calculating:

$P_{\mathrm{est}}=\frac{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}[\mathrm{ri}\left(k\right)\·\mathrm{rq}\left(k\right)]}{K\sqrt{\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|\mathrm{ri}\left(k\right)\right|}^2\·\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left|\mathrm{rq}\left(k\right)\right|}^2}}k=1\·\·\·K$

Step c2 calculates the arcsine value of described angle, and described arcsine value is defined as I signal behind the described amplitude correction and the phase difference θ of Q signal.

Concrete by following formula calculating:

θ＝arc?sin(P _est)

Step S407 carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively according to described phase difference.

After I signal after counting amplitude correction and the phase difference of Q signal, still the I signal behind the above-mentioned amplitude correction and Q signal are as primary signal, respectively the I signal behind the described amplitude correction and Q signal are carried out the phase place correcting process, thereby reach the purpose that eliminates unbalance in phase.

This step S407 specifically comprises:

Step C1 is defined as the I signal behind each amplitude correction respectively the revised I signal of each phase place, is specially:

ri ₃(k)＝ri ₂(k)，k＝1…K

Wherein, ri ₃(k) be the revised I signal of phase place.

Step C2, the sine value with the I signal behind each amplitude correction and described phase difference multiplies each other respectively, obtains the first numerical value, and the Q signal behind described the first numerical value and the described amplitude correction is corresponding one by one.

Step C3 deducts the Q signal behind each amplitude correction respectively first numerical value corresponding with it, obtains second value.

Step C4 respectively with the cosine value of each second value divided by described phase difference, obtains the revised Q signal of each phase place.

Above-mentioned steps C2-step C4 specifically can calculate by following formula:

${\mathrm{rq}}_3\left(k\right)=\frac{{\mathrm{rq}}_2\left(k\right)-{\mathrm{ri}}_2\left(k\right)\·\sin \left(\mathrm{\θ}\right)}{\cos \left(\mathrm{\θ}\right)},k=1\·\·\·K$ Formula 4

Above-mentioned formula 4 can also be reduced to:

${\mathrm{rq}}_3\left(k\right)=\frac{{\mathrm{rq}}_2\left(k\right)-{\mathrm{ri}}_2\left(k\right)\&CenterDot;P_{\mathrm{est}}}{\sqrt{1-{\mathrm{<figure-callout\; id="2"\; label="P\; est"\; filenames="HDA00002107893400011.png"\; state="\{\{state\}\}">P</figure-callout>}}_{\mathrm{est}}^{}}},k=1\&CenterDot;\&CenterDot;\&CenterDot;K$

Wherein, rq ₃(k) be the revised Q signal of phase place.

With reference to Fig. 5, show the schematic diagram of the described statistics direct current leakage of the embodiment of the present application amount, Amplitude Ratio and phase difference.Dc_ri is the direct current leakage amount of I signal among the figure, and dc_rq is the direct current leakage amount of Q signal, and gi is the Amplitude Ratio of the revised I signal of direct current and Q signal, and θ is I signal behind the amplitude correction and the phase difference of Q signal.

With reference to Fig. 6, show the schematic diagram of the described direct current correction of the embodiment of the present application, amplitude correction and phase place correction, wherein, Ri and Rq are respectively I signal and the Q signal that the zero intermediate frequency feedback signal is sampled and obtained.For the detailed process of revising, get final product with reference to above-mentioned associated description, present embodiment is discussed no longer in detail at this.

Fig. 7 is the schematic diagram of the overall process of the described statistics of the embodiment of the present application and correction, wherein, Ri and Rq are respectively I signal and the Q signal that the zero intermediate frequency feedback signal is sampled and obtained, Ri1 and Rq1 are respectively the revised I signal of direct current and Q signal, Ri2 and Rq2 are respectively I signal and the Q signal behind the amplitude correction, Ri3 and Rq3 are respectively the revised I signal of phase place and Q signal, and T1, T2, T3 all are delayers.For concrete statistics and the process of correction, get final product with reference to above-mentioned associated description, present embodiment is discussed no longer in detail at this.

Need to prove, in above-mentioned Fig. 5-7, included only the situation that described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, be the situation of the ratio of described summation amp_ri and described summation amp_rq for described Amplitude Ratio, those skilled in the art carry out respective handling according to actual conditions and get final product, and the application discusses no longer in detail at this.

Step S408 carries out the processing of digital pre-distortion coefficient update to the revised I signal of phase place and Q signal, obtains I signal to be sent and Q signal.

After I signal and Q signal are carried out the phase place correction, also to carry out the digital pre-distortion coefficient update to the revised I signal of phase place and Q signal and process, thereby obtain I signal to be sent and Q signal.As shown in Figure 2, wherein, described digital pre-distortion coefficient update is processed and is comprised synchronous calibration, pre-distortion coefficients estimation and pre-distortion.

When carrying out the processing of digital pre-distortion coefficient update, what DPD adopted is memory multinomial (Memory-Polynomial, MP) model, is a special case of Volterra progression, is shown below:

$F\left[x\left(n\right)\right]=\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}\underset{m=0}{\overset{M-1}{\mathrm{\&Sigma;}}}{w}_{\mathrm{km}}x(n-m){\left|x(n-m)\right|}^{k-1}$

The target of DPD coefficient update process will be tried to achieve the predistortion model exactly | F () |.

The estimation of DPD coefficient is to obtain by feedback signal and the contrast that transmits.Feedback signal Y and the Z that transmits finish after the time delay calibration, also need the calibration of the amplitude of carrying out.Feedback signal is used the rms amplitude calibration method with transmitting in the embodiment of the present application, so that | y|=|z|, like this before adaptive-filtering, feedback signal and the amplitude that transmits are basically identical, so the multinomial that obtains of assessment is processed function | F () |=||, therefore can't change the amplitude of signal.Remain unchanged thereby derive the output signal F (x) of high speed predistorter and the amplitude of input signal x, namely | F (x) |=| x|, so namely satisfied DPD output front and back power and kept constant characteristics.

Preferably, the zero intermediate frequency feedback signal that feeds back for the DPD feedback path in the embodiment of the present application all is kept among the RAM, as shown in Figure 8, is that the embodiment of the present application is described for the uneven data access schematic diagram that carries out in the makeover process of zero intermediate frequency feedback.

When need to be to being stored in zero intermediate frequency feedback signal among the RAM when carrying out statistical disposition, from RAM, directly extract a calculated signals once, put into again RAM after calculating is finished, directly the data among the RAM are revised in the time of correction, need not to open up new space, saving resource.

To be that the embodiment of the present application three is described a kind ofly feed back the structured flowchart of unbalanced update the system for zero intermediate frequency to Fig. 9, and described system comprises:

Sampling module 901 is used for the zero intermediate frequency feedback signal is sampled, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature;

Direct current correcting module 902, for the direct current leakage amount of adding up respectively described I signal and Q signal, and the described direct current leakage amount of foundation is carried out the direct current correcting process to described I signal and Q signal respectively;

Amplitude correction module 903, for the Amplitude Ratio of the statistics revised I signal of direct current and Q signal, and the described Amplitude Ratio of foundation carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively;

Phase place correcting module 904, for the I signal behind the statistics amplitude correction and the phase difference of Q signal, and the described phase difference of foundation carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively;

Update module 905 is used for the revised I signal of phase place and Q signal are carried out the processing of digital pre-distortion coefficient update, obtains I signal to be sent and Q signal.

Wherein, described direct current correcting module 902 comprises:

I signal direct current leakage amount computing unit for the mean value dc_ri that calculates all I signals of sampling in the Preset Time section, is defined as described mean value dc_ri the direct current leakage amount of I signal;

Q signal direct current leakage amount computing unit for the mean value dc_rq that calculates all Q signals of sampling in the described Preset Time section, is defined as described mean value dc_rq the direct current leakage amount of Q signal;

I signal direct current amending unit, the direct current leakage amount for respectively each I signal of sampling in the described Preset Time section being deducted described I signal obtains the revised I signal of each direct current;

Q signal direct current amending unit, the direct current leakage amount for respectively each Q signal of sampling in the described Preset Time section being deducted described Q signal obtains the revised Q signal of each direct current.

Described amplitude correction module 903 comprises:

I signal summation computing unit is for the summation amp_ri that calculates the revised I signal of all direct currents;

Q signal summation computing unit is for the summation amp_rq that calculates the revised Q signal of all direct currents;

The Amplitude Ratio computing unit is used for calculating the ratio of described summation amp_ri and described summation amp_rq, and the perhaps ratio of described summation amp_rq and described summation amp_ri is defined as described ratio the Amplitude Ratio of the revised I signal of described direct current and Q signal;

The first I signal amplitude correction unit is used for when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, respectively the revised I signal of each direct current is defined as the I signal behind each amplitude correction;

The first Q signal amplitude correction unit is used for respectively the revised Q signal of each direct current and described Amplitude Ratio being multiplied each other when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, obtains the Q signal behind each amplitude correction;

The second I signal amplitude correction unit is used for respectively the revised I signal of each direct current and described Amplitude Ratio being multiplied each other when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, obtains the I signal behind each amplitude correction;

The second Q signal amplitude correction unit is used for when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, respectively the revised Q signal of each direct current is defined as the Q signal behind each amplitude correction.

In the embodiment of the present application, the I signal composition of vector RI behind all amplitude corrections, the Q signal composition of vector QI behind all amplitude corrections,

Described phase place correcting module 904 comprises:

The angle computing unit is for the angle that calculates described vectorial RI and described vectorial QI;

The phase difference calculating unit is used for calculating the arcsine value of described angle, and described arcsine value is defined as I signal behind the described amplitude correction and the phase difference of Q signal;

I signal phase place amending unit is used for respectively the I signal behind each amplitude correction being defined as the revised I signal of each phase place;

The unit that multiplies each other is used for respectively the sine value of the I signal behind each amplitude correction and described phase difference is multiplied each other, and obtains the first numerical value, and the Q signal behind described the first numerical value and the described amplitude correction is corresponding one by one;

Addition unit is used for the Q signal behind each amplitude correction being deducted first numerical value corresponding with it respectively, obtains second value;

Q signal phase place amending unit is used for respectively with the cosine value of each second value divided by described phase difference, obtains the revised Q signal of each phase place.

Described update module 905 comprises: synchronous calibration unit, pre-distortion coefficients evaluation unit and pre-distortion unit.Wherein:

The synchronous calibration unit is used for the revised I signal of phase place and Q signal are carried out synchronous calibration;

The pre-distortion coefficients evaluation unit is used for the I signal behind the synchronous calibration and Q signal are carried out the pre-distortion coefficients estimation;

The pre-distortion unit is used for utilizing described pre-distortion coefficients that I signal and Q signal are carried out pre-distortion.

Get final product for the function of concrete synchronous calibration unit, pre-distortion coefficients evaluation unit and the pre-distortion unit associated description with reference to said method embodiment, present embodiment is discussed no longer in detail at this.

For system embodiment because itself and embodiment of the method basic simlarity, so describe fairly simple, relevant part gets final product referring to the part explanation of embodiment of the method.

In sum, the embodiment of the present application is described feeds back unbalanced modification method and system has following advantage for zero intermediate frequency:

(1) provides a kind of and fed back unbalanced modification method and system for zero intermediate frequency in the DPD feedback path, when receiving the zero intermediate frequency feedback signal, at first it is revised, again the signal after revising is carried out the digital pre-distortion coefficient update and process, thereby make the I signal to be sent and the Q signal that obtain more accurate.

(2) propose at first to carry out statistics and the correction of direct current leakage, then take the correction result of direct current as the basis, carry out statistics and the correction of amplitude imbalance, take the correction result of amplitude as the basis, carry out statistics and the correction of unbalance in phase again.Sample for the zero intermediate frequency feedback signal that the DPD feedback path once feeds back, can carry out statistics and the makeover process of above-mentioned three kinds of situations, and need not repeatedly iteration, improved treatment effeciency.

(3) the zero intermediate frequency feedback signal that feeds back for the DPD feedback path all is kept among the RAM, when need to be to being stored in zero intermediate frequency feedback signal among the RAM when carrying out statistical disposition, from RAM, directly extract a calculated signals once, after finishing, calculating puts into again RAM, directly the data among the RAM are revised when revising, need not to open up new space, saving resource.

Each embodiment in this specification all adopts the mode of going forward one by one to describe, and what each embodiment stressed is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.

The application can describe in the general context of the computer executable instructions of being carried out by computer, for example program module.Usually, program module comprises the routine carrying out particular task or realize particular abstract data type, program, object, assembly, data structure etc.Also can in distributed computing environment (DCE), put into practice the application, in these distributed computing environment (DCE), be executed the task by the teleprocessing equipment that is connected by communication network.In distributed computing environment (DCE), program module can be arranged in the local and remote computer-readable storage medium that comprises memory device.

For aforesaid each embodiment of the method, for simple description, so it all is expressed as a series of combination of actions, but those skilled in the art should know, the present invention is not subjected to the restriction of described sequence of movement, because according to the present invention, some step can adopt other orders or carry out simultaneously.Secondly, those skilled in the art also should know, the embodiment described in the specification all belongs to preferred embodiment, and related action and module might not be that the present invention is necessary.

At last, also need to prove, in this article, relational terms such as the first and second grades only is used for an entity or operation are made a distinction with another entity or operation, and not necessarily requires or hint and have the relation of any this reality or sequentially between these entities or the operation.And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, thereby not only comprise those key elements so that comprise process, method, commodity or the equipment of a series of key elements, but also comprise other key elements of clearly not listing, or also be included as the intrinsic key element of this process, method, commodity or equipment.Do not having in the situation of more restrictions, the key element that is limited by statement " comprising ... ", and be not precluded within process, method, commodity or the equipment that comprises described key element and also have other identical element.

More than a kind ofly feed back unbalanced modification method and system for zero intermediate frequency to what the application provided, be described in detail, used specific case herein the application's principle and execution mode are set forth, the explanation of above embodiment just is used for helping to understand the application's method and core concept thereof; Simultaneously, for one of ordinary skill in the art, the thought according to the application all will change in specific embodiments and applications, and in sum, this description should not be construed as the restriction to the application.

Claims (18)

1. one kind is fed back unbalanced modification method for zero intermediate frequency, it is characterized in that, comprising:

The zero intermediate frequency feedback signal is sampled, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature;

Add up respectively the direct current leakage amount of described I signal and Q signal, and respectively described I signal and Q signal are carried out the direct current correcting process according to described direct current leakage amount;

The Amplitude Ratio of the statistics revised I signal of direct current and Q signal, and the described Amplitude Ratio of foundation carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively;

I signal behind the statistics amplitude correction and the phase difference of Q signal, and the described phase difference of foundation carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively;

The revised I signal of phase place and Q signal are carried out the processing of digital pre-distortion coefficient update, obtain I signal to be sent and Q signal.

2. method according to claim 1 is characterized in that, described step of adding up respectively the direct current leakage amount of described I signal and Q signal comprises:

Calculate the mean value dc_ri of all I signals of sampling in the Preset Time section, described mean value dc_ri is defined as the direct current leakage amount of I signal;

Calculate the mean value dc_rq of all Q signals of sampling in the described Preset Time section, described mean value dc_rq is defined as the direct current leakage amount of Q signal.

3. method according to claim 2 is characterized in that, the described direct current leakage amount of described foundation comprises the step that described I signal and Q signal carry out the direct current correcting process respectively:

Respectively each I signal of sampling in the described Preset Time section is deducted the direct current leakage amount of described I signal, obtain the revised I signal of each direct current;

Respectively each Q signal of sampling in the described Preset Time section is deducted the direct current leakage amount of described Q signal, obtain the revised Q signal of each direct current.

4. according to claim 1 or 3 described methods, it is characterized in that the step of the Amplitude Ratio of the revised I signal of described statistics direct current and Q signal comprises:

Calculate the summation amp_ri of the revised I signal of all direct currents;

Calculate the summation amp_rq of the revised Q signal of all direct currents;

Calculate the ratio of described summation amp_ri and described summation amp_rq, the perhaps ratio of described summation amp_rq and described summation amp_ri is defined as described ratio the Amplitude Ratio of the revised I signal of described direct current and Q signal.

5. method according to claim 4 is characterized in that, when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq,

The described Amplitude Ratio of described foundation carries out the step that amplitude correction processes to the revised I signal of described direct current and Q signal respectively and comprises:

Respectively the revised I signal of each direct current is defined as the I signal behind each amplitude correction;

Respectively the revised Q signal of each direct current and described Amplitude Ratio are multiplied each other, obtain the Q signal behind each amplitude correction.

6. method according to claim 4 is characterized in that, when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri,

The described Amplitude Ratio of described foundation carries out the step that amplitude correction processes to the revised I signal of described direct current and Q signal respectively and comprises:

Respectively the revised I signal of each direct current and described Amplitude Ratio are multiplied each other, obtain the I signal behind each amplitude correction;

Respectively the revised Q signal of each direct current is defined as the Q signal behind each amplitude correction.

7. method according to claim 1 is characterized in that, the I signal composition of vector RI behind all amplitude corrections, and the Q signal composition of vector QI behind all amplitude corrections,

The step of the I signal behind the described statistics amplitude correction and the phase difference of Q signal comprises:

Calculate the angle of described vectorial RI and described vectorial QI;

Calculate the arcsine value of described angle, described arcsine value is defined as I signal behind the described amplitude correction and the phase difference of Q signal.

8. method according to claim 7 is characterized in that, the described phase difference of described foundation comprises the step that the I signal behind the described amplitude correction and Q signal carry out the phase place correcting process respectively:

Respectively the I signal behind each amplitude correction is defined as the revised I signal of each phase place;

Sine value with the I signal behind each amplitude correction and described phase difference multiplies each other respectively, obtains the first numerical value, and the Q signal behind described the first numerical value and the described amplitude correction is corresponding one by one;

Respectively the Q signal behind each amplitude correction is deducted first numerical value corresponding with it, obtain second value;

With the cosine value of each second value divided by described phase difference, obtain the revised Q signal of each phase place respectively.

9. method according to claim 1 is characterized in that, described digital pre-distortion coefficient update is processed and comprised synchronous calibration, pre-distortion coefficients estimation and pre-distortion.

10. one kind is fed back unbalanced update the system for zero intermediate frequency, it is characterized in that, comprising:

Sampling module is used for the zero intermediate frequency feedback signal is sampled, and described zero intermediate frequency feedback signal comprises mutually Q signal of homophase I signal and quadrature;

The direct current correcting module, for the direct current leakage amount of adding up respectively described I signal and Q signal, and the described direct current leakage amount of foundation is carried out the direct current correcting process to described I signal and Q signal respectively;

The amplitude correction module, for the Amplitude Ratio of the statistics revised I signal of direct current and Q signal, and the described Amplitude Ratio of foundation carries out the amplitude correction processing to the revised I signal of described direct current and Q signal respectively;

The phase place correcting module, for the I signal behind the statistics amplitude correction and the phase difference of Q signal, and the described phase difference of foundation carries out the phase place correcting process to the I signal behind the described amplitude correction and Q signal respectively;

Update module is used for the revised I signal of phase place and Q signal are carried out the processing of digital pre-distortion coefficient update, obtains I signal to be sent and Q signal.

11. system according to claim 10 is characterized in that, described direct current correcting module comprises:

I signal direct current leakage amount computing unit for the mean value dc_ri that calculates all I signals of sampling in the Preset Time section, is defined as described mean value dc_ri the direct current leakage amount of I signal;

Q signal direct current leakage amount computing unit for the mean value dc_rq that calculates all Q signals of sampling in the described Preset Time section, is defined as described mean value dc_rq the direct current leakage amount of Q signal.

12. system according to claim 11 is characterized in that, described direct current correcting module also comprises:

I signal direct current amending unit, the direct current leakage amount for respectively each I signal of sampling in the described Preset Time section being deducted described I signal obtains the revised I signal of each direct current;

Q signal direct current amending unit, the direct current leakage amount for respectively each Q signal of sampling in the described Preset Time section being deducted described Q signal obtains the revised Q signal of each direct current.

13. according to claim 10 or 12 described systems, it is characterized in that described amplitude correction module comprises:

I signal summation computing unit is for the summation amp_ri that calculates the revised I signal of all direct currents;

Q signal summation computing unit is for the summation amp_rq that calculates the revised Q signal of all direct currents;

The Amplitude Ratio computing unit is used for calculating the ratio of described summation amp_ri and described summation amp_rq, and the perhaps ratio of described summation amp_rq and described summation amp_ri is defined as described ratio the Amplitude Ratio of the revised I signal of described direct current and Q signal.

14. system according to claim 13 is characterized in that, described amplitude correction module also comprises:

The first I signal amplitude correction unit is used for when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, respectively the revised I signal of each direct current is defined as the I signal behind each amplitude correction;

The first Q signal amplitude correction unit is used for respectively the revised Q signal of each direct current and described Amplitude Ratio being multiplied each other when described Amplitude Ratio is the ratio of described summation amp_ri and described summation amp_rq, obtains the Q signal behind each amplitude correction.

15. system according to claim 13 is characterized in that, described amplitude correction module also comprises:

The second I signal amplitude correction unit is used for respectively the revised I signal of each direct current and described Amplitude Ratio being multiplied each other when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, obtains the I signal behind each amplitude correction;

The second Q signal amplitude correction unit is used for when described Amplitude Ratio is the ratio of described summation amp_rq and described summation amp_ri, respectively the revised Q signal of each direct current is defined as the Q signal behind each amplitude correction.

16. system according to claim 10 is characterized in that, the I signal composition of vector RI behind all amplitude corrections, and the Q signal composition of vector QI behind all amplitude corrections,

Described phase place correcting module comprises:

The angle computing unit is for the angle that calculates described vectorial RI and described vectorial QI;

The phase difference calculating unit is used for calculating the arcsine value of described angle, and described arcsine value is defined as I signal behind the described amplitude correction and the phase difference of Q signal.

17. system according to claim 16 is characterized in that, described phase place correcting module also comprises:

I signal phase place amending unit is used for respectively the I signal behind each amplitude correction being defined as the revised I signal of each phase place;

The unit that multiplies each other is used for respectively the sine value of the I signal behind each amplitude correction and described phase difference is multiplied each other, and obtains the first numerical value, and the Q signal behind described the first numerical value and the described amplitude correction is corresponding one by one;

Addition unit is used for the Q signal behind each amplitude correction being deducted first numerical value corresponding with it respectively, obtains second value;

Q signal phase place amending unit is used for respectively with the cosine value of each second value divided by described phase difference, obtains the revised Q signal of each phase place.

18. system according to claim 10 is characterized in that, described update module comprises:

The synchronous calibration unit is used for the revised I signal of phase place and Q signal are carried out synchronous calibration;

The pre-distortion coefficients evaluation unit is used for the I signal behind the synchronous calibration and Q signal are carried out the pre-distortion coefficients estimation;

The pre-distortion unit is used for utilizing described pre-distortion coefficients that I signal and Q signal are carried out pre-distortion.

Images